后缘裂缝充水对裂口山滑坡稳定性的影响

The numerical simulation on landslide stability to chasm mountain landslide affected by water filling at trailing edge chasm

通过分析裂口山滑坡的GPS专业监测位移资料,初步判定其变形与降雨入渗存在一定联系,采用离散元程序3DEC 5.0模拟降雨条件下后缘裂缝充水对滑坡变形、应力状态及稳定性的影响。结果表明:裂口山滑坡后缘裂缝充水产生的滑体变形主要表现为局部变形,滑体底部水平位移明显大于顶部,且后缘裂缝内水头越高,滑体综合水平位移越大;水头H在25 m附近变化时,对滑体综合水平位移影响最为敏感。裂口山滑坡后缘裂缝内的静水压力所产生的推力不足以使该滑坡启动,后缘裂缝充水前后,底部滑面各点的有效正应力下降幅度较大,即滑面抗剪强度大幅降低,但对其稳定性影响不大。裂缝充水前后,并随着水头高度的增加,稳定系数变幅不大,滑体仍能保持稳定状态。

The displacement data of professional GPS monitoring of chasm mountain landslide is analyzed, to preliminary assume the relationship between deformation and rainfall infiltration. Under the condition of water filling in the back edge crack, the deformation, stress state and stability is simulated through the discrete element method, to study the effect of water pressure on chasm mountain landslide. The results show that the deformation caused by the water pressure in trailing edge chasm is mainly local, and the horizontal displacement at the bottom of the sliding body is significantly greater than the top, and the higher the water head at trailing edge chasm, the comprehensive horizontal displacement is larger. The comprehensive horizontal displacement is the most sensitive when the water head variation Around 25 meters. The thrust produced by water in trailing edge chasm is not enough to make the landslide. Before and after water filling in the trailing edge chasm, the effective normal stress on sliding surface reduce a lot, while the stability of the whole landslide changes slightly. So the chasm mountain landslide could keep stable state no matter the water head in trailing edge chasm.